JEE Advance - Physics (2021 - Paper 2 Online - No. 19)
In a photoemission experiment, the maximum kinetic energies of photoelectrons from metals P, Q and R are EP, EQ and ER, respectively, and they are related by EP = 2EQ = 2ER. In this experiment, the same source of monochromatic light is used for metals P and Q while a different source of monochromatic light is used for the metal R. The work functions for metals P, Q and R are 4.0 eV, 4.5 eV and 5.5 eV, respectively. The energy of the incident photon used for metal R, in eV, is ___________.
Answer
6
Explanation
EP = 2EQ = 2ER = E(assume)
For metal P and Q,
E1 - 4 = EP = E ……..(1)
E1 - 4.5 = EA = E/2 ……..(2)
Subtracting equation (2) from (1), we get
E/2 = 0.5
For metal R
E2 - 5.5 = ER = E/2 = 0.5
$$ \Rightarrow $$ E2 = 6
Comments (0)
